Slide switch

ABSTRACT

A slide switch in which either of fixed or movable contact elements have electrically high resistance portions formed at portions where fixed and movable contact elements start to contact with each other and at portions where fixed and movable contact elements start to move away from each other.

United States Patent Appl. No, Filed Patented Assignee Priority SLIDE SWITCH 4 Claims, 4 Drawing Figs.

US. Cl 200/11 D,

Int. Cl l-I0lh l/02, HOlh 1/06, HOlh 19/58 Field of Search 200/ l 6, 166 C, l l

[56] References Cited UNITED STATES PATENTS 2,216,654 10/1940 Seubert 1 200/166 C 2,307,668 1/1943 Cox 200/166 C X 3,174,000 3/1965 Golbeck 200/16 X 3,205,332 9/1965 Price et al.. 200/166 C 3,234,351 2/1966 Hebb 200/166 C X 3,302,270 2/1967 Grabbe... 200/166 C X 3,324,269 6/1967 La Roy 200/166 C 3,327,081 6/1967 Pflanz 200/166 C X 3,514,559 5/1970 Ranheim 200/166 C X Primary Examiner-.l. R. Scott AttorneyBurgess, Ryan and Hicks ABSTRACT: A slide switch in which either of fixed or movable contact elements have electrically high resistance portions formed at portions where fixed and movable contact elements start to contact with each other and at portions where fixed and movable contact elements start to move away from each other.

SLIDE swrrcn BACKGROUND OF THE INVENTION The present invention relates to a slide switch and more particularly a slide switch in which either of fixed or movable contact elements have electrically high-resistance portions formed at portions where fixed and movable contact elements start to contact with each other and at portions where fixed and movable contact elements start to move away from each other.

Arcs of sparks are generally produced between fixed and movable contact elements of a switch having such contact elements incorporated therein when the switch is opened and closed because of the inductance of its electric circuit and/or load thereof. Therefore, carbide or sulfide coatings are produced upon the surfaces of the contact elements, so that the electrical contact between the fixed and movable contact elements is adversely affected. Furthermore, the contact elements tend to be fused or melted because of the arcs and sparks therebetween. The arcs and sparks tend to occur especially when the fixed and movable contact elements start to contact with each other and move away from each other because of an excess transient current flow.

A typical conventional slide switch will be described with reference to Fig. 1. Fixed contact elements 2, 3, 3, 4, 5 and 5', terminals 6, 7, 8 and 9 and movable contacts 10 and 11 which are rotated in the direction indicated by the arrows, are supported upon a member 1 made of an insulating material. The current flows from the terminal 6-through fixed contact 2 contact lfixed contacts 3 and 3'to terminal 7 or from terminal 8 through fixed contact 4movable contact 11- fixed contacts and 5--to terminal 9.

In this slide switch, all of the contacts are made of homogeneous conductor material and the portions 3a, 3a, 5a and 5'a of the fixed contacts 3, 3, 5 and 5 respectively at which the movable contacts 10 and 11 start to contact with and move away from the fixed contacts 3, 3, 5 and 5 respectively are also made of homogeneous conductor material with other portions of contacts. Thus, when the switch is closed and opened, the above-described troubles inevitably occur.

SUMMARY OF THE INVENTION A slide switch in accordance with the present invention is such that either of fixed or movable contact elements have electrically high-resistance portions formed at portions where fixed and movable contact elements start to contact with each other and at portions where fixed and movable contact elements move away from each other.

Because of the provision of these electrically high-resistance portions formed at portions of either of fixed or movable contact elements, an excess transient current can be positively prevented, so that not only the arcs or sparks between the fixed and movable elements can be prevented but also a slide switch in accordance with the present invention can be fabricated without effecting much modification in construction of conventional slide switches.

BRIEF DESCRIPTION OF THE DRAWING FIGS. 1 and 2 are plan views illustrating a conventional switch and a slide switch in accordance with the present invention respectively; and

FIG. 3A is a cross-sectional view of the contact structure taken along lead line 3A-3A in FIG. 2.

v Fig. 38 illustrates a modified embodiment of the fixed contact structure.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to Fig. 2 illustrating one embodiment of the present invention, the portions 3b, 3'12 5b and 5'!) which correspond to the portions 3a, 3'a, 5a and S'a of the contacts 3, 3, 5 and 5 are made of a material having a relatively high electrical resistance. When the slide switch is closed, the movable contact 10 or 11 first make contact with the high-resistance portions 3b, 3'b or 5b and S'b, so that relatively small current flows. But when the movable contact 10 or 11 passes beyond these high-resistance portions 3b and 3b or 5b and S'b, the movable contact I0 or 11 contacts the portions each having a predetermined resistance, so that a predetermined current flows. There is no fear that excess current flows when the moving contact contacts with the fixed one, so that the trouble encountered in the conventional slide switch can be effectively eliminated. When the circuit is opened, the transient current may be prevented.

As shown in FIGS. 3A and 3B, the fixed contact 3 may be provided with a high-resistance portion 3b which may be overlaid upon the contact 3 or coated or formed by any suitable chemical process, as long as the high resistance portion 3b is provided for the sake of the accomplishment of the present invention. It should be noted that the high-resistance portion 3b in FIG. 3A is shown as having the upper surface higher than that of the contact 3, but this is for facilitating the understanding of the invention. The upper surface of the high-resistance portion 3b is in coplanar relation with the upper surface of contact 3 in Fig. 3B.

It will be appreciated that the high-resistance portion can be formed on the movable contact instead of the fixed contact when the former is larger in size than the latter.

Iclaim:

I. In combination with a slide switch having an arcuately shaped fixed contact portion and a slide contact arcuately moving thereacross to make and break electrical contact therewith comprising:

the fixed contact having at least one stepped configuration including an upstanding portion adapted to be contacted by the slide contact; said upstanding portion including a first part having a predetermined electrical resistance to How of electricity;

said upstanding portion including a second part having an electrical resistance to the flow of electricity greater than the resistance of said first part; and

said second part located in an end portion of said upstanding portion to prevent arcing between said fixed and slide contacts with respect to relative movement of said fixed and slide contacts.

2. The combination of claim I in which a plurality of stepped upstanding portions are provided, and each said upstanding portion includes one said second part to prevent arcing when said slide contact first makes an electrical connection and when said slide contact breaks the electrical connection.

3. The combination of claim 1 in which said second part is overlaid upon said upstanding portion to form a raised surface thereon to be contacted by said slide contact.

4. The combination of claim I in which said second part is formed within said upstanding portion so that an upper surface of said second part is coplanar with an upper surface of said upstanding portion. 

1. In combination with a slide switch having an arcuately shaped fixed contact portion and a slide contact arcuately moving thereacross to make and break electrical contact therewith comprising: the fixed contact having at least one stepped configuration including an upstanding portion adapted to be contacted by the slide contact; said upstanding portion including a first part having a predetermined electrical resistance to flow of electricity; said upstanding portion including a second part having an electrical resistance to the flow of electricity greater than the resistance of said first part; and said second part located in an end portion of said upstanding portion to prevent arcing between said fixed and slide contacts with respect to relative movement of said fixed and slide contacts.
 2. The combination of claim 1 in which a plurality of stepped upstanding portions are provided, and each said upstanding portion includes one said second part to prevent arcing when said slide contact first makes an electrical connection and when said slide contact breaks the electrical connection.
 3. The combination of claim 1 in which said second part is overlaid upon said upstanding portion to form a raised surface thereon to be contacted by said slide contact.
 4. The combination of claim 1 in which said second part is formed within said upstanding portion so that an upper surface of said second part is coplanar with an upper surface of said upstanding portion. 